Locking device for aviation trainers



, March 18, 1947. w.,D. JONES" 17,55

LOCKING DEVICE FOR AVIATION 'TRAINEiiS Filed March 5, 1945 FIG.

W|LL|AM D'JONES INVENTOR.

*fi u/xfi I I TO EYS latented Mar. 18, 1947 LOCKING DEVICE FOR AVIATION TRAINERS William D. Jones, Houston, Tex., assignor to Link Aviation Devices, Inc., Binghamton, N. Y., a corporation of New York Application March 5, 1945, Serial No. 581,043

10 Claims. ((11. s 12) My invention relates to locking or leveling devices for aviation trainers of the universally mounted type such as are disclosed in U. S. Patents 1,825,462 and 2,099,857.

Trainers of the type disclosedin these two patents are generally referred to as Link trainers and they comprise a fuselage having a seat for a student, the fuselage being mounted upon a universal joint which is held by a vertical spindle rotatably mounted in a stationary base which rests upon the floor or ground. Rigidly aflixed to the main vertical spindle is an octagon to which is attached the bottom end of four collapsible-expansible bellows, the upper ends of these bellows being afiixed to the bottom of the fuselage. Two of the bellows (the climb-dive or pitching bellows) are in line with the longitudinal axis of the fuselage while the othertwo bellows (the banking bellows) are in line with the transverse axis of the fuselage. Within the fuselage there is placed controls simulating the pitching and banking controls of a real plane. These controls are connected to the bellows insuch a manner that when the banking control is moved in a manner that would cause a plane in actual flight to bank to the left, the left banking bellows is collapsed and the right banking bellows is expanded so that the fuselage banks to the left. An opposite movement of the banking control results in a contraction of the right banking bellows, an expansion of the left banking bellows, and the fuselage banks to the right. If the pitching control in the fuselage is moved in simulation of the manner that a pilot of a real plane would move the corresponding control to place the planein a diving attitude, the forward pitching bellows collapses, the rearward pitching bellows expands, and the trainer assumes a diving attitude. On the other hand if the pitching control is moved in the opposite direction, the rear pitching bellows contracts, the forward pitching bellows expands, and the fuselage assumes a climbing attitude.

The proper expansion and contraction of these bellows in response to a movement of the simulated controls within the trainer is accomplished by the provision of a source of vacuum in the form of a turbine, this source being connected to the bellows through two valvesa pitching valve and an aileron valve. As is well known in the prior art, the aileron valve is arranged to be responsive to the movements of the simulated banking control means in the trainer so as to" properly admit vacuum and air to the banking bellows in response 'to a movement of the simulated banking control means, whereby the trainer is placed in the proper banking position according to the movements of the simulated banking control means. Similarly, the pitching valve is properly responsive to the movements of the simulated pitching control i selage is placed in the proper pitching attitude in means within the fuselage so that vacuum and air are selectively admitted to the pitching bellows inresponse to movements of the simulated pitching control means whereby the trainer furesponse to a movement of the simulated control means.

When the student is in the fuselage flying a problem, the turbine is energized and by virtue of the explained construction the student may control the fuselage to position it about its longitudinal and transverse axes as desired. However it will be appreciated that upon the termination of the problem it is advantageous to stop the turbine and when this is done, the bellows are no longer effective to keep the fuselage level with respect to the stationary base; It therefore becomes necessary that means be provided for keeping the trainer fuselage level after the turbine has been shut off. Such means should preferably be operable by the student within the fuselage so that the fuselage may be securely leveled upon the universal joint before he makes his exit from the trainer.

This problem has been appreciated by previous inventors and the United States Patents 2,360,- 34.6, and 2,360,882 have been issued upon locking and leveling devices for aviation trainers of the type being considered. Both of these patents disclose a more or less complicated cable arrangement for leveling the trainer fuselage. It is the main object of my invention to provide a simpler, cheaper and more satisfactory operating locking device for aviation trainers of the universally mounted type.

In order that the nature of my invention may be better understood referenceis made to the accompanying drawings wherein a preferred embodiment of my invention is disclosed.

In the drawings,

Fig. 1 is a side view of a Link trainer showing the general positioning of the parts of my invention, a portion of the fuselage being cut away to show a part of my invention.

Fig. 2 is a detailed schematic view of the type of locking means with which my invention is concerned, and Fig. 2A is a detailedvlew of "a portion of the apparatus shown in Fig. 2. i i

Fig. 3 is a partial front view of a Link trainer showing the general positioning of certain parts of my invention.

As is well known in the prior art, trainers of the type being considered comprise a stationary base l shown in Fig. 1 which rests upon the floor or ground. A fuselage I2 is provided having therein a seat (not shown) suitable for the use of a student. The fuselage l2 rests upon a universal joint designated generally by 14, this joint being held by a main central vertical spindle l6 which is rotatably mounted in the stationary base Ill. An octagon l3 encircling the spindle I6 is provided, this octagon being suitably attached by arms (not shown) to the vertical spindle [6 so that the octagon rotates with the vertical spindle. A turning motor 29 carried by the supporting arms 22 which are attached to the octagon 18 forms a part of these trainers and a turning belt 24 encirzles a pulley upon the output shaft of the turning motor as well as a-fixed pulley which is attached to the stationary base 10. The turning motor 20 is connected to the turbine 26 through a rudder valve which is actuated by a pair of simulated rudder pedals (not shown) in the fuselage l2. When the student in the fuselage I2 presses the left rudder pedal forward the output shaft of the turning motor 20 is turned in one direction and the turning motor 20, supporting arms 22, the octagon [8, vertical spindle l6, universal joint I 3 and fuselage l2 are turned by the turning belt about a vertical axis in the counterclockwise direction as seen from above, or to the left. On the other hand, when the student in the traine presses the right rudder pedal forward, the rudder valve is positioned so that the output shaft of the turning motor 28 turns in the opposite direction and the same parts are rotated about the vertical axis toward the right. It should be particularly noted that the oztagon 18, vertical spindle l6, universal joint I4 and fuselage l2 always rotate together about a vertical axis, this rotation simulating the turning of a plane in actual flight.

Still referring to Fig. 1, it will be seen that the forward pitching bellows 28 and the rear pitching bellows 39 are carired by the octagon l8 for, rotation therewith. The bottom sides of these bellows are affixed to the cross arms which connect the octagon l8 and vertical spindle Hi. The rear pitching bellows 30 has its upper end attached to the bottom of the fuselage l2 by the link 32 and the forward pitching bellows 28 is similarly attached to the bottom of the fuselage I2. Within the fuselage I2 is the control column designated generally by 34, this control column comprising a generally vertical member 36 pivoted at the point 38 and a rotatably mounted wheel 40 carried by the upper end of the vertical member 36. When the student in the fuselage l2 pushes the wheel 40 so that the upper end of the vertical member 33 moves toward the head of the fuselage I2, the pitching valve in the fuselage i2 is moved to such a position that vacuum from the turbine 26 is admitted through a suitable air line to the interior of the bellows 28. Simultaneously the pitching valve admits air to the rear pitching bellows 30. Bellows 28 therefore contracts and at the same time bellows 3E! expands so the fuselage l2 moves about a transverse axis through the universal joint It, the fore end of the fuselage being lowered and the rear end elevated, The fuselage is therefore placed in a position simulating the diving position of a plane in actual flight. An opposite movement of the memher 36 actuates the pitching valve so that vacuum is admitted to the bellows 30, air is admitted to the bellows 28 and the fuselage l2 assumes a climbing attitude.

In Figs. 1 and 3 the right banking bellows 42 and left banking bellows 53 are shown. These bellows are plazed upon the opposite side of the universal joint 14 and have their upper ends connected to the bottom of the fuselage l2 by the members 45. When the wheel 49 is moved counterclockwise by the student, vacuum is admitted to the left banking bellows 43 through the action of the aileron valve, air is admitted to the right banking bellows 32 and the trainer i2 moves about a longitudinal axis through the universal joint It so that the fuselage l2 assumes a left banking position. An opposite movement of the wheel ib actuates the aileron valve to admit vacuum to the right banking bellows 42 and air to the left banking bellows 23, the former contracting and the latter expanding, resulting in a banking of the fuselage l2 to the right.

All of the foregoing structure is disclosed in the above mentioned United States Patents 1,825,462 and 2,099,857 and therefore forms no part of my invention except when combined with the novel structure later to be disclosed.

In view of the foregoing discussion it will be appreciated that when the turbine 26 is deenergized, the pressure within the pitching and banking bellows becomes neutralized and these bellows will no longer support the fuselage 12 upon the universal joint [4 in the desired attitude. The fuselage !2 will, therefore, in the absence of suitable restraining structure assume a position about the longitudinal and transverse axes through the universal joint dependent upon the location of the center of gravity of the fuselage l2. The following means forming a preferred embodiment of my invention may be employed to prevent this movement of the fuselage 12 after the turbine is stopped.

Reference is now made to Fig. 2 which discloses in detail the preferred embodiment of my locking device. In Fig. 2 a portion of the octagon i8 is shown and it will be seen that a bracket M is fixedly attached to the octagon l8 by means of bolts 46. As best seen in Fig. 2A, there are suitably rigidly affixed to the bracket 44, as by welding, a pair of circular bearings 48. A main locking arm 51] is provided and there is rigidly affixed to the lower end of this arm, as by welding, a tubular member 52. When these parts are assembled, a pin 54 passes through the bearings 48 as well as the tubular member 52 and a spring clip 55 may be attached to either end of the pin 54 to prevent axial movement of this pin. With this arrangement the locking arm 50 is pivotally held by the bracket 44. The upper end of the locking arm 50 has a hole 53 therein, and upon the side of the fuselage I2 is rigidly affixed by bolts 60 the plate 62 which has integral therewith a tapered engaging stud 64 adapted to pass through the hole 58 in the upper end of the looking arm 59.

In Fig. 2 it will be seen that there is a bracket 66 affixed to the inside of the octagon I8 by means of bolts 68 and the fixed side ll] of the airproof bellows designated generally 12 is carried by bracket 66. Bellows 12 comprises a side 14 pivotally attached to the fixed side 10 along the lower ends thereof 18. This bellows may be made airproof by meansof a suitable cloth covering such as is well known in the art. Aflixed to the outside of the pivoted portion 14 of bellows 12 is the member 18 to which is affixed the inner end of the reciprocating link 80 which passes through the hole 82 in the octagon 18. The outer end of the link 80 is afiixed to the inner side of the locking member 5|] by means of suitable screws 84 at a point between the upper and lower ends of the locking arm 50. A spring 85 has its inner end anchored to the octagon l8 and its outer end is suitably afiixed to the locking arm 50. This spring, it will be appreciated, exerts a pressure upon the locking arm 50 tending to move the upper end of this locking arm toward the fuselage I2. I

In Fig. 2 it will be seen that a vacuum-air line 88 is provided, the lower end of this air line being in airtight connection with the interior of the bellows 12 and the upper end of this air line being similarly connected to one end of the T-connector 9G. The central portion 92 of the T-connector 99 extends upwardly within the fuselage l2 to the two-port valve 94 which is located as shown in Fig. 1. Valve 94 connects the line 92 with the atmosphere through port 96 and also connects member 92 with the turbine 26 through the line 98. A suitable control arm In!) is pro vided whereby the student in the fuselage l 2 may selectively operate valve 94 to connect the line 82 with the atmosphere or turbine 26, as desired.

Figs. 1 and 3 show the general location with respect to the octagon I8 and fuselage 12 of the main parts of my invention shown in detail in Fig. 2, and in Fig. 3 it will be seen that my inven tion employs two locking arms 50, and therefore two bellows i2 and associated parts shown in Fig. 2. However, only one T-connector 99, valve 94 and source of vacuumis used. In Figs. 1 and 3 it will be seen that the locking arms 50 are placed on the same side of the transverse axis through the universal joint l4 and toward the head of the fuselage l2 from this transverse axis. However, it should be noted that the locking arms are placed upon opposite sides of the longitudinal axis through this universal joint, as clearly illustrated in Fig. 3.

In order to illustrate the manner in which my apparatus may be used for the purposes outlined above, let us assume that the student is in the fuselage l2 flying the same. Under these circumstances the student places the control arm [ill] in such a position that the two bellows 12 are in communication with the turbine 26. It will be appreciated that the turbine 26 will exhaust the air within the bellows l2 and that the pivoted sides 14 of both of these bellows will be pushed by the outside atmospheric pressure against the fixed sides of each of the bellows. The links 80 will therefore be pushed outwardly through the holes 82 in the octagon I8 against the tension of the springs 36 and the upper ends of the locking arms 58 will be pushed outwardly from the fuselage l2 so that the upper ends become disengaged from the studs 6 5. Thus the student may, by means of the column 38 and wheel 48 within the fuselage, pitch and bank the fuselage as desired and the locking arms 50 will not interfere with these conventional fuselage movements.

Now let us assume that the student in the fuselage I2 has finished his problem and that he wishes to make his exit from the fuselage. The control arm In!) is moved so that the turbine 25 is disconnected from both of the bellows l2 and so that the bellows 12 are connected with the atmosphere through the port 96. The introduction of atmosphere into bellows l2 and the tension of springs 86 will pull the upper ends 6 of the locking arms 50 toward the fuselage If. The student in the fuselage l2 merely levels the fuselage by means of the conventional instruments in the fuselage, such as the artificial horizon, and when the fuselage is so leveled the studs 64 will protrude through the holes 58 in the upper ends of the locking arms 50. The springs 86 will maintain the studs 64 in this position and the student may then shut off the ignition switch conventionally placed in the fuselage, thereby deenergizing the turbine 26. (It should be noted that the upper ends of the locking arms are flanged outwardly so that the studs 64 will not engage the upper ends of the arms 50 to prevent a downward movement of the fore end of the fuselage when the arms 50 are pulled inwardly.)

It will be appreciated that the apparatus of my invention will then prevent any movement of the fuselage 12 about the axes through the universal joint l4 and that the fuselage 12 will be maintained in a level position until the next problem is started.

When the succeeding student enters the fuselage ii to begin his problem, the ignition switch in the trainer is turned on, the turbine 25 is energized and therefore the bellows again become effective for controlling the attitude of the fuselage. The arm liltl is moved to disconnect the port 86 with the bellows 12 and to connect the turbine 26 with the bellows 12. The bellows 72 are then collapsed and by means of the arm 8ii the upper ends of the locking arms 50 are disengaged from the studs 64. The conventional controls in the trainer may then be used to pitch and bank the trainer as desired without inter ference from the apparatus of my invention.

It will be appreciated that certain modifications may be made in the preferred embodiment of my invention without departing from the substance thereof and that the apparatus of my invention need not be placed with respect to the fuselage l2 and octagon l8 exactly as shown. Also my invention may be used in connection with apparatus other than grounded aviation trainers. All such modifications and uses are intended to be covered by the following claims.

I claim:

1. In combination with a grounded navigation trainer comprising a fuselage mounted upon a universal joint for movement about an axis longitudinal of said fuselage and about an axis transverse of said fuselage and having a lower member positioned below said fuselage and universal joint, 2. locking device for maintaining said fuselage in the level position when said trainer is not in use, saidlocking device comprising a pair of rigid arms each having an upper and a lower end, means attached to said fuselage for engaging the upper ends of each of said arms and means attached to said lower member for engag ing the lower ends of each of said arms; and a versal joint, a locking device for maintaining said fuselage in the level position when said trainer is not in use, said locking device comprising a pair of rigid arms each having an upper and a lower end; means attached to said fuselage for engaging the upper ends of each of said arms and means attached to said lower memher for engaging the lower ends of each of said arms, each of said arms being pivoted at one of its ends; and a manually operable control connected to said arms and located inside said fuselage so as to be under the control of an operator therein for selectively pivoting said arms about their pivoted ends to engage and disengage the engaging means at their unpivoted ends.

3. In combination with a grounded navigation trainer comprising a fuselage mounted upon a universal joint for movement about an axis longitudinal of said fuselage and about an axis transverse of said fuselage and having a lower member positioned below said fuselage and unl versal joint, a locking device for maintaining said fuselage in the level position when said trainer is not in use, said locking device comprising a pair of rigid arms each having an upper and a lower end; means attached to said fuselage for engaging the upper ends of each of said arms and means attached to said lower member for en gaging the lower ends of each of said. arms, each of said arms being pivoted at one of its ends; a collapsible-expansible member connected to each of said arms for pivoting said arms about their pivoted ends; and means under the control of an operator for selectively collapsing and expanding said collapsible-expansible member.

4. In combination with a grounded navigation trainer comprising a fuselage mounted upon a universal joint for movement about axis longitudinal of said fuselage and about an. axis transverse of said fuselage and having a lower member positioned beiow said fuselage and universal joint, a locking device for maintainingsaid fuselage in the level position when said trainer is not in use, said locking device comprising a pair of rigid arms each having an upper and lower end; means attached to said fuselage for engaging the upper ends of each of said arms and means attached to said lower member for engaging the lower ends of each of said arms, each of said arms being pivoted at one of its ends; a collapsible-expansible member connected to each of said arms for pivoting said arms in one direction about their pivoted ends; means connected to each of said arms for pivoting said arms in the opposite direction about their pivoted ends; and means under the control of an operator for selectively operating either of said arm-pivoting means.

5. In combination with a grounded navigation trainer comprising a fuselage mounted upon a universal joint for movement about an axis longitudinal of said fuselage and about an axis transverse of said fuselage and having a member positioned below said fuselage and universal joint, a locking device for maintaining said fuselage in the level position when said trainer is not in use, said locking device comprising a rigid arm having an upper and a lower end; means attached to said fuselage for engaging the upper end of said arm and means attached to said lower member for engaging the lower end of said arm, one of said engaging means comprising a pivot; and a manually operable control connected to said arm and located inside said fuselage so as to be under the control of an operator therein for selectively pivoting said arm in either direction to engage and disengage the unpivoted end of said arm with respect to the engaging means at the unpivoted end of said arm.

6. In combination with a grounded navigation trainer comprising a fuselage mounted upon a universal joint for movement about an axis longitudinal of said fuselage and about an axis transverse of said fuselage and having a member positioned below said fuselage and universal joint, a locking device for maintaining said fuselage in the level position when said trainer is not in use, said locking device comprising a rigid arm having an upper and a iower end; means attached to said fuselage for engaging the upper end of said arm and means attached to said lower member for engaging the lower end of said arm, one of said engaging means comprising a pivot; a collapsibleexpansible member connected to said arm for pivoting the same in one direction; a fiuid source and a valve; a connection between said fluid source and said valve and a connection between said valve and said collapsible-expansible member; control means for operating said valve to pivot said arm in one direction; and means for pivoting said arm in the opposite direction.

7. In combination with a grounded navigation trainer comprising a fuselage mounted upon a universal joint for movement about an axis longitudinal of said fuselage and about an axis transverse of said fuselage and having a member positioned below said fuselage and universal joint, a locking device for maintaining said fuselage in the level position when said trainer is not in use, said locking device comprising a rigid arm having an upper and a, lower end; means attached to said fuselage for engaging the upper end of said arm and means attached to said lower member for engaging the lower end of said arm, one of said engaging means comprising a pivot; a pneumatically operated bellows connected to said arm for pivoting the same; and a valve connected to said bellows and under the control of an operator for operating said bellows.

8. In combination with a grounded navigation trainer comprising a fuselage mounted upon a universal joint for movement about an axis longitudinal of said fuselage and about an axis transverse of said fuselage and having a member positioned below said fuselage and universal joint, a locking device for maintaining said fuselage in the level position when said trainer is not in use, said locking device comprising a rigid arm having an upper and a lower end; means attached to said fuselage for engaging the upper end of said arm and means attached to said lower memher for engaging the lower end of said arm, one of said engaging means comprising a pivot; a penumatically operated bellows connected to said arm for pivoting the same in one direction; a valve connected to bellows and under the control of an operator for operating said bellows; and means for pivoting said arm in the opposite direction.

9. In combination with a grounded navigation trainer comprising a fuselage mounted upon a universal joint for movement about an axis longitudinal of said fuselage and about an axis transverse of said fuselage and having a member positioned below said fuselage and universal joint, a locking device for maintaining said fuselage in the level position when said trainer is not in use, said locking device comprising a rigid arm having an upper and a lower end; a stud attached to said fuselage for engaging the upper end of said arm and means attached to the lower end of said arm for pivotally holding the same; and a manually operable control connected to said arm and located inside said fuselage so as to be under the control of an operator therein for selectively pivoting said arm in either direction to engage and disengage the upper end of said arm from said stud. V

10. In combination with a grounded navigation trainer comprising a fuselage mounted upon a universal joint for movement about an axis longi-- tudinal of said fuselage and about an axis transverse of said fuselage and having member positioned below said fuselage and universal joint, a locking device for maintaining said fuselage in the level position when said trainer is not in use, said locking device comprising a rigid arm having an upper and a lower end; a stud attached to said fuselage for engaging the upper end of said arm and means attached to the lower end of 10 said arm for pivotally holding the same; a pressure operated bellows connected to said arm for pivoting the same; and a valve connected to said bellows and under the control of an operator for operating said bellows.

WILLIAM D. JONES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,825,462 Link Sept. 29, 1931 1,865,828 Buckley July 5, 1932 2,063,231 Custer Dec. 8, 1936 2,099,857 Link Nov. 23, 1937 2,360,346 Holloman 0ct.'17, 1944 

